The present invention pertains to a special-purpose, special-capability, breathable, friction- and shear-controlling, anatomical-support, pressure-evenizing, “mattress overlay” intended to be placed on top of, and used in conjunction with, an underlying, yieldable support surface, such as that provided by a mattress, for the purpose of furnishing “direct”, pressure-evenizing under-support for a substantially bed-ridden person. In particular, the invention relates to an improved version of the invention described in the above-referenced '568, immediate-parent patent application.
The invention, described herein principally, at least initially, in the realm of structure, also concerns methodology which is associated with this overlay.
The overlay of the invention is specifically designed, as will be explained more fully below, with thinness suitable, with appropriate, yieldable under-support, for handling persons weighing up to about 350-lbs. It is definitively not designed to be used alone as a support on top of any rigid, underlying surface; nor is it intended to be a “stand-alone” support structure, such as a mattress, per se. Where heavier persons need to be accommodated, this may be done, as will also be explained more fully below, by placing the overlay on top of an additional, bariatric, under-support structure.
Accordingly, the herein-proposed overlay, in its preferred and best-mode form, has a thickness which is preferably no more than about 1-inches. This preferred thickness militates against its utilization respecting the “not-designed-for” uses just above mentioned.
The term “bed-ridden” as used herein as a “person characterization” is intended broadly to include a wide range of differently convalescing persons who may spend significant amounts of extended, body-support time not only specifically in hospital beds, but also on and in conjunction with other bed-like mattress structures.
Speaking with more particularity about the invention, and about what we see to be its remarkable, and experimentally demonstrated capability, it, the proposed “mattress overlay”, has as its special purpose the dramatic minimization, and in many instances the complete prevention, of the onset and development of decubitus ulcers(sores)—medical conditions that lead to dangerous and potentially lethal injuries which come from long-term body-rest/support conditions. Accordingly, the overlay of the present invention is naturally, and particularly, well suited for placement on top of conventional, long-term, person/patient-support mattresses, such as hospital-bed mattresses. While such a hospital-bed setting clearly presents an ideal use environment for the present invention, the defining term “mattress overlay” is intended herein to refer to any overlay structure constructed in accordance with the special and unique features of the present invention which may be shaped, sized, etc., for use not only on top of an underlying, conventional mattress structure, per se, but also in other similar environments where nonambulatory people, such as convalescing patients, may lie recurrently supported for long periods of time. The above-expressed concept of “direct”, underlying, person support, while it could (and can) include the concept of direct-to-skin contact support, herein more typically means support which is furnished, for example, (a) “directly through” clothing (such pajamas, a hospital gown, etc.), (b) through a bed sheet, or (c) through some combination of these and like things.
Regarding the above-mentioned special purpose of the present invention, it is now, and has been for some time, well recognized that the medical issue involving the development of decubitus ulcers in bed-ridden, etc., patients, often those people who are still in the environment of a hospital recovering from some medical event or condition, is an extremely serious problem—a problem which has recently caught the significant negative attention of medical-institutional (and related) insurance agencies who have come to recognize that prevention of the development of such ulcers is, in fact, quite possible, though through conventional approaches very challenging. This “negative attention” has translated itself, among other things, into agency refusals to offer/provide relevant insurance coverage. While the just-mentioned term “quite possible” is indeed true, real prevention—that is, effective real prevention—heretofore has been almost prohibitively expensive because of the fact that such prevention has, in reality, required substantial, frequent, personnel-intensive, one-to-one, or more-to-one, personal attendance to the changing of the resting “positions” of “bed-ridden” persons at risk.
The decubitus ulcer (decubitus-onset, decubitus-injury, decubitus-injury onset) problem is recognized today as being one of the most serious problems facing hospital and medical-care facilities, and these skilled care facilities are openly waging a fierce battle with state and federal agencies and insurance companies over who should pay the enormous costs in the treatment of this “new epidemic.”
In this setting, the prior art, of which we are aware, that has been aimed at addressing the “decubitus-injury” problem is rich with purportedly effective, proposed approaches for resolving it. In practice, none appears to be particularly successful or satisfactory, owing, as we perceive it, to the significant and apparent failure to grasp a comprehensive understanding of the key body-support environmental and contact conditions which must exist if decubitus “onset” is to be avoided. The present invention, we believe, “possesses” this understanding, for, in months of experimental use, involving thousands of patient-support days, and hundreds of bed-ridden patients, there have been almost no instances of decubitus-injury onset.
Presently known (to us), patent-related pieces of this prior art include: U.S. Patent Application Publication No. 2001/0034908 A1 of Duly, for “Mattress”; U.S. Pat. No. 5,031,261 to Fenner, Sr., for “Mattress Overlay For Avoidance of Decubitus Ulcers”; U.S. Pat. No. 5,077,849 to Farley, for “Anatomically Conformable Foam Support Pad”; U.S. Pat. No. 6,052,851 to Kohnle, for “Mattress For Minimizing Decubitus Ulcers”; U.S. Pat. No. 7,356,863 to Oprandi, for “Mattress Pad”.
While these identified, prior-art approaches address, and attempt to tackle with resolution, certain technical medical issues and conditions that can lead to the development of a decubitus injury (frequently referred to as a decubitus ulcer), clearly taking aim at successfully minimizing costly medical-personnel attention to “decubitus-at-risk” individuals, as far as we can tell, no one has successfully developed a truly effective support structure and/or methodology which has(have) the capabilities of substantially eliminating, in most instances, the likelihood that such a decubitus ulcer will develop.
The present invention dramatically changes this situation. While readings and study of this prior art, when compared with a reading of the present invention disclosure, may appear at first glance, and on certain points, to reveal only subtle differences, in reality these differences, in terms of solving the problem of decubitus onset, are anything but subtle. Put another way, these differences “make the difference”!
While there are probably many issues that are usefully addressable in terms of preventing decubitus ulcers, the three, key considerations which we specially recognize in the methodology and structure of the present invention involve:
(a) (1) avoiding even very short-term (minutes) of high, applied anatomical pressure, (2) at all times pressure-evenizing the contact-loading characteristics which define how the anatomy of a bed-ridden patient is supported, and (3) specifically producing an anatomical loading condition, static and dynamic, whereby there exist substantially no notably high-pressure points (preferably none exceeding about 32-mm Hg, and even more preferably not exceeding about 20-mm Hg), and definitively no conditions involving a projecting portion of the person's anatomy (i.e., a protuberance) bottoming out against either a non-yielding, or relatively non-yielding, underlying support surface, or in any manner significantly raising (de-evenizing) anatomical support pressure;
(b) minimizing friction and shear engagement between the proposed overlay structure and a supported patient; and
(c), very importantly, providing effective, ventilating, heat-removing airflow (more broadly, gas flow) in the region immediately beneath the contact-supported anatomy so as to avoid the development of hot-spots and overheating, and especially recognizing that those portion of a supported anatomy, such as bony prominences, which create notable, downward “indentations” in an underlying support structure should be offered proportionally larger access to air (gas) flow.
Stressing this just-identified, third, heat-removal, airflow-associated concern, and repeating, with emphasis, the “proportionally” greater airflow comment just made above, it is especially relevant that the points/areas/regions of underlying anatomical support which must deal with the mentioned, notable, anatomical protuberances, and especially with pronounced (i.e., relatively “sharp”) protuberances, be designed to furnish locally enhanced, rather than more constricted, airflow within the anatomical support structure. Put another way such protuberance-support areas are the ones that potentially define the greatest risk for decubitus-ulcer development, and as we have discovered, are the areas where the most robust, ventilating airflow and air-circulation capability need to exist. Generally speaking, the greater the size and/or “sharpness” of the protuberance, and thus the greater and the deeper and the more angular the resulting support-surface indentation, the greater the need for enhanced, support-structure airflow and air-circulation capability.
Unfortunately, known and proposed prior art manners of attacking the decubitus-ulcer problem do not recognize this special, anatomical-protuberance-support observation of ours, and failing that observation, actually propose supposedly problem-resolving body-support structures and associated methodologies which exacerbate the airflow problem associated with protuberance support by reacting to downward protuberances with either no attention paid to airflow, or even worse, increased constriction to airflow.
With this background in mind, the present invention, in its structural character, takes the form of an anatomical pressure-evenizing mattress overlay including (a) a dynamic-response, preferably uniform-thickness core expanse having spaced, upper and lower, surfaces and a perimetral edge extending between these surfaces, formed of a 100% open-cell, uniform-density compressible and flowable, viscoelastic foam, and having a “relaxed-state” volume in the overlay which is prestressed, by being about 8-10% compressed, to create a pre-stressed, pre-compression condition in the expanse, and (b) a differential-thickness, elastomeric, vinyl coating having, due to differential thickness, specifically different moisture-handling and gas-breathability characteristics furnished importantly at different, selected locations in the overlay (as will shortly be explained). This coating, which is referred to herein as an at least partially gas-breathable coating (quite freely breathable on the edges of the overlay), is load-transmissively, interfacially bonded to the entirety of the outside surface area of the core expanse to function as a dynamically-responsive unit with the expanse—this coating possessing a “relaxed-state”, internal, prestressed tension condition which is responsible for the pre-stressed, pre-compression condition in the core expanse. The term “relaxed-state” herein is used to refer to the conditions of the components (two) making up the pad when the pad is in a non-use situation.
The core expanse is specifically and preferably formed of a specific-character, solid-phase, single-component, single-density, polyurethane material, shaped with its upper and lower surfaces substantially equidistant (i.e., the core expanse has preferably a uniform thickness) to give the overlay, as a whole, a substantially uniform thickness of no more than about 1-inches, with the differential-thickness coating having a thickness of about 0.01-inches on and along the elongate, “vertically central” regions of the overlay edges, and about 0.02-inches elsewhere—dimensional matters of choice, but specifically found to be very useful, and consequently “preferred”.
Accordingly, and for important structural and performance reasons which will be explained later herein regarding the coating, immediately outwardly (from the core expanse) beyond an initially created, overall primer sublayer (which flows into the core expanse material—an open cell foam material), the coating, distributed in an all-over configuration relative to the core expanse, is formed therefore on both the overlays perimetral edges and on its broad-surface areas, and specifically is preferably formed with ten, approximately 0.001-inches thick, cured, sublayers. These ten sublayers, further, are preferably spray-applied, one over another, under “wet-form”, interlayer bonding circumstances, where the “previously applied”, next-spray-receiving sublayer, including the mentioned primer sublayer (which adds substantially no depth to the coating, per se), is still wet and not yet cured.
Different-thickness (greater-thickness) coating portions cover the two broad-surface areas in the overlay, as well as two, vertically spaced, upper and lower bands of the overlay's perimetral edge regions. These thicker coating portions include outer, eleventh, individually thicker (about 0.01-inches) sublayers which are sprayed onto the immediately underlying, ten, thinner, “all-over, basic” sublayers after those underlying basic sublayers have dried. These thicker coating portions form moisture-shielding (impervious), core-protection “caps” covering the opposite faces and nearby, perimetral, lateral-edge regions of the core expanse, and define, in the space between them, the previously mentioned, elongate, vertically central regions of the overlay's laterally outwardly facing perimeter to define effective, and important, lateral breathability for the overlay's core expanse.
The just-mentioned, wet-interlayer sublayer joinder methodology (and arrangement) employed in relation to the preferred, ten, basic sublayers in the coating produces, structurally, a final, cured, layered coating having, between substantially all next-adjacent, basic sublayers, and between the innermost, basic sublayer and the primer sublayer, what we refer to structurally herein as being finally cured, but initially wet, interfacial surfaces of joinder. We have found that this special type of wet, interfacial joinder structure enhances not only the gas-breathability characteristics of the overall coating, but also, importantly, the controlled shrinkage of the coating to produce the desired level of coating-internal tension, and core-expanse-internal compression. The one “area”, however, and as was just pointed out, of the prepared coating wherein the wet-interfacial joinder approach is not employed involves the application to each of the broad facial areas in the overlay of the final, eleventh coating sublayer.
Regarding the selectively differential gas-breathability aspects of the proposed coating (i.e., what may be thought of as being the coating “permeability-differentiating” features), the two (upper- and lower-face) broad-area regions of the coating in the overlay, and the two, vertically spaced, perimetral “bands” of extra-thickness coating sublayers which join with these broad-area regions, are structured with their respective, eleventh, outermost, 0.01-inch-thickness sublayers formed so as to be substantially both moisture-impervious and gas-impermeable in nature, whereas the associated, ten, next-inner, “basic” sublayers are structured to be both moisture-resistant (but moisture-pervious) and gas-permeable.
One practical and successful way of creating the coating to possess the mentioned sublayers with the respective, desired thicknesses and differential-permeability characteristics is set forth later herein.
The detailed description of the invention which follows below will describe fully the features of, and the importances attached to, the matters of core-expanse-material flowability, coating tension, core-expanse compression, coating-core-expanse mechanical binding to one another, and coating “permeability-differentiating” features.
The overlay, per se, which is elongate and generally planar in nature, has no preferential upper or lower end, and no preferential top or bottom face, or side. It can, accordingly, confidently be placed with any suitable orientation on an appropriate supporting under-structure.
From a methodologic general perspective, the invention involves a method for furnishing pressure-evenized, dynamic-reaction support for the anatomy including (a) supporting the anatomy with a 100% open cell, polyurethane, viscoelastic foam, and following such supporting, and within the supporting foam, reacting therein to both static and dynamic, anatomical-unevenness-produced indentations in the foam to expand and contract foam cell-openness size, whereby deeper and sharper foam indentations result in greater cell-openness size.
These and other features and advantages offered by the present invention will become more fully apparent as the detailed description which now follows is read in conjunction with the accompanying drawings.